1. Field of the Invention
This invention relates to an audio system that minimizes the wires that are used to electrically couple the speakers thus minimizing the chances that high power audio signals may be directed to a headphone jack.
2. Related Art
A speaker system is commonly hooked up to an audio system such as those typically found in desktop and laptop computers to enhance the listening experience. A typical computer based speaker system generally may include left and right satellite speakers typically placed on either side of the computer, and possibly a subwoofer is usually located nearby. The subwoofer may be larger than the two satellite speakers because of its larger diaphragm typically required for production of bass sounds. The subwoofer may house a power amplifier and controls for the speaker system. By placing the controls on the subwoofer, audio system control management is often inconveniently located. For convenience, a speaker system may provide controls on one of the satellite speakers so the controls are within the reach of the listener to adjust the volume, treble, and bass. Besides these controls, a headphone output for private listening may be provided with the speaker system or computer system.
Cables may be used to provide power and audio signals to all of the speakers. Each cable may have more than ten wires to provide all of the control functionality to the satellite speakers and the headphone connection. Using ten or more wires, however, can make the cable bulky, stiff, and expensive to manufacture. Asthetically, with all of the wires feed into the rear panel on of the computer presents a cluttered and unappealing appearance. In addition, the additional wires increases the number of connectors. However, besides increasing manufacturing costs, connectors are an unreliable component creating opportunities for system failure, malfunction or noise.
Others have tried to minimize the number of wires in a speaker system by transmitting power, control, and audio signals through shared wires. Using one wire for multiple purposes, however, can cause signal interference. As the control signals are transmitted via the same wire carrying power for the speaker, signal interference may create audible artifacts in the audio signal. Thus, using one wire for multiple purposes can degrade the quality of the sound that is produced by the speaker system, as well as create other malfunctions.
In addition to the controls, the satellite speakers may have headphone jack hookups. When the headphone plug is inserted into the jack, a switching mechanism is usually provided to provide audio signals to the headphone rather than to the loudspeakers, i.e., the satellite speakers and the subwoofer. The switching mechanism generally reacts to contacts or the mechanical motion of the plug being inserted into the jack. This scheme creates a potential risk to a user when the headphone plug is initially inserted into the headphone jack. One alternative is to make electrical contact before the mechanical switch is actuated, thereby redirecting the high power signal for the loudspeaker to the headphone. However, this could either damage the earpieces in the headphones or injure the listener's ear.
Therefore, a need exists for (1) preventing high power audio signals from being directed to the headphone jack and (2) a speaker system that minimizes the number of wires that are used without implementing shared signal wires.